This invention relates to an improved method for the production of folding door and wall shells made of rigid panels or lamellae.
In such shells textile joint inserts are attached on the outside of the basic panel body, which may consist of chipboards. The joints inter-connect adjacent panels and cover up vertical expansion joints. An outside cover of veneer corresponds in height and width to the dimensions of the panel and leaves only a small strip of the joint insert exposed. On the reverse side of the shell the panels are limited from one another by V-shaped grooves.
A folding door comprises a rigid steel scissors frame which is covered on both sides by shells of the type described. This construction permits an accordion-like folding of the entire door over its full width.
In applicants' U.S. Pat. No. 3,708,009 a process is described according to which shells of the above described type are produced. The cover veneer corresponding to the panels is detachably and "negatively" secured, with the viewing or face side down, to a separate carrier board, and grooves are milled through the cover veneer in the area of future expansion joints between the panels. Hinge inserts are independently applied to a panel plate over further grooves which are covered by the inserts. The carrier board and the panel plate are then interconnected at their applied layers such that their respective grooves lie in the same cross-sectional planes. The carrier board is subsequently detached from the cover veneer so that the latter remains adhered to the panel plate and the hinge inserts, and possibly to a cross grain oriented veneer layer. V-shaped grooves are subsequently milled into the reverse side of the panel plate to define the adjacent panels.
This process is not only cumbersome and expensive because of the use of a separate carrier board, but the mutual alignment of the cover veneer and expansion joints on the panel plate is very difficult.